Radiation imagery chemistry: process – composition – or product th – Dye image from radiation sensitive dye or dye former by dry... – Composition or product
Reexamination Certificate
1999-12-20
2001-10-30
Schilling, Richard L. (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Dye image from radiation sensitive dye or dye former by dry...
Composition or product
C430S201000, C008S471000, C008S687000, C503S227000, C534S831000
Reexamination Certificate
active
06309807
ABSTRACT:
The present invention relates to a disazo dye having a specific structure useful for thermal transfer recording, particularly for thermal transfer recording of dye-transferring type, and a thermal transfer sheet and an ink for thermal transfer recording, employing such a dye.
The thermal transfer recording of dye-transferring type is a recording method wherein a thermal transfer sheet having an ink layer containing a thermally transferable dye formed on a base film is overlaid on an image-receiving sheet having an image-receiving layer on its surface, and the thermal transfer sheet is heated to transfer the dye in the thermal transfer sheet to the image-receiving sheet thereby to carry out recording. This recording method is applied to full color image recording by e.g. a video printer, since it is thereby possible to control the transfer amount of the dye by the quantity of the thermal energy and thereby to carry out gradation expression.
In the thermal transfer recording of dye-transferring type, the dye to be used for the thermal transfer sheet and the ink composition for the thermal transfer sheet, is very important, as it substantially influences over the speed of the thermal transfer recording, the image quality and storage stability of the recorded product, and such a dye is required to satisfy the following conditions.
{circle around (1)} It readily sublimates or thermally diffuses under the operational condition of the thermal recording head.
{circle around (2)} It undergoes no thermal decomposition under the operational condition of the thermal recording head.
{circle around (3)} It has a desirable color for color reproduction.
{circle around (4)} It has a large molecular extinction coefficient.
{circle around (5)} It is stable against heat, light, moisture, chemicals, etc.
{circle around (6)} It is easy to prepare.
{circle around (7)} It is suitable for preparation of an ink.
{circle around (8)} It has no problem for safety.
As disazo dyes for thermal transfer recording to satisfy such conditions, JP-A-60-180889 discloses a dye having no OR
1
group in the formula (I) of the present invention and a dye having a substituent (a methyl group) on the phenyl group which connects the two disazo groups in the formula (I) of the present invention.
However, the dyes disclosed in the publication are required to be further improved with respect to the color density, light resistance and color tone on the sheet or recorded product.
It is an object of the present invention to provide a disazo dye which exhibits excellent performance in all of the above properties {circle around (1)} to {circle around (8)} as a dye for a thermal transfer recording of dye-transferring type, and a thermal transfer sheet and an ink for thermal transfer recording, employing such a disazo dye.
Under these circumstances, present inventors have conducted an extensive study and as a result, have found that a disazo dye having a certain specific structure is a yellow dye which satisfies the above conditions and which is excellent in the balance of all of the color density, light resistance and color tone. The present invention has been accomplished on the basis of this discovery.
Namely, the present invention provides a disazo dye for thermal transfer recording of the following formula (I):
wherein each of rings A and B which are independent of each other, is a benzene ring which may have a substituent, R
1
is a C
1-4
substituted or unsubstituted alkyl group, and R is a group selected from the group consisting of a hydrogen atom and a C
1-4
substituted or unsubstituted alkyl group, and a thermal transfer sheet and an ink for thermal transfer recording, employing such a dye.
Now, the present invention will be described in detail with reference to the preferred embodiments.
The structural characteristics of the disazo dye of the present invention are such that rings A and B have certain specific substituents, and the benzene ring at the center is unsubstituted.
In the disazo dye of the formula (I) of the present invention, the C
1-4
substituted or unsubstituted alkyl group for R
1
may, for example, be a straight chain or branched chain alkyl group, and specifically, it may, for example, be a methyl group, an ethyl group, a n-propyl group, an i-propyl group, a n-butyl group or an i-butyl group. The substituent may, for example, be an alkoxy group, an alkoxyalkoxy group, an aryloxy group, an allyloxy group, an aralkyloxy group, an aryl group, a cyano group, a hydroxyl group, a halogen atom, an alkoxycarbonyl group, an allyloxycarbonyl group or an acyloxy group. If the carbon number of R
1
is too large, the color density tends to be low. Accordingly, R
1
is preferably a methyl group or an ethyl group, most preferably a methyl group. Further, R
1
is preferably an unsubstituted alkyl group.
The C
1-4
substituted or unsubstituted alkyl group for R
2
may, for example, be a straight chain or branched chain alkyl group, and specifically, it may, for example, be a methyl group, an ethyl group, a n-propyl group, an i-propyl group, a n-butyl group or an i-butyl group. The substituent may, for example, be an alkoxy group, an alkoxyalkoxy group, an aryloxy group, an allyloxy group, an aralkyloxy group, an aryl group, a cyano group, a hydroxyl group, a halogen atom, an alkoxycarbonyl group, an allyloxycarbonyl group or an acyloxy group.
If the carbon number of R
2
is too large, the color density tends to be low. Accordingly, R
2
is preferably a methyl group or an ethyl group, more preferably a methyl group or an ethyl group, most preferably a methyl group. Further, R
2
is preferably an unsubstituted alkyl group. The position for substitution of R
2
is not particularly limited, but it is particularly preferred that R
2
is substituted at the meta-position to the carbon atom on ring B on which the azo group is substituted, i.e. at the ortho-position to the carbon atom on which the hydroxyl group is substituted, as the light resistance is thereby good.
Each of rings A and B is a benzene ring which may further have a substituent, and the substituent may, for example, be an alkyl group, an alkoxy group, a halogen atom, a hydroxyl group, a nitro group, a cyano group, an alkoxycarbonyl group, an alkylsulfonyl group or an acylamino group. The number of substituents on ring A or B may be two or more, and in such a case, the plurality of substituents may be the same or different from one another.
Among the dyes of the present invention, a dye of the following formula (II):
wherein each of R
1′
and R
2′
which are independent of each other, is a group selected from the group consisting of a methyl group and an ethyl group, is a dye having a novel structure, and it is a preferred dye which is easy to prepare and which exhibits excellent performance with a good balance of the color density, light resistance and color tone of the recorded product. Among them, a dye of the formula (II) wherein each of R
1′
and R
2′
is a methyl group, is most preferred from the viewpoint of the color density.
Now, specific examples of the dye of the formula (I) will be shown below.
TABLE 1
(I)
No. 1
No. 2
No. 3
No. 4
No. 5
No. 6
No. 7
No. 8
No. 9
No. 10
Now, a synthesis of the disazo dye of the formula (I) of the present invention will be described. Firstly, an aniline of the following formula (III):
wherein R
1
and A are as defined in the formula (I), is diazotized by a conventional method, followed by coupling with a compound of the following formula (IV):
and the reaction solution is alkalized and heated to synthesize a monoazo compound of the following formula (V):
wherein R
1
and A are as defined in the formula (I). Then, the monoazo compound (V) is further diazotized, followed by coupling with a compound of the following formula (VI):
wherein B and R
2
are as defined in the formula (I), to obtain the disazo dye of the formula (I) of the present invention.
The thermal transfer sheet of the present invention usually contains at least one type of the dye of the above formula (I) in
Ishida Mio
Maeda Koji
Murata Yukichi
Mitsubishi Chemical Corporation
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Schilling Richard L.
LandOfFree
Disazo dye for thermal transfer recording and thermal... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Disazo dye for thermal transfer recording and thermal..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Disazo dye for thermal transfer recording and thermal... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2608872